- Fixed Streamline method

- Fixed Streamline method
- Added FindTag method to Line
- Added DumpTree method for debugging
- Added DecrementLines() method for deleting lines
- Fixed UpdateView to update the cursor to end-of-line on single-line updates
- Added PositionCaret() method
- Fixed MoveCaret(LineDown) to move into the last line, too
- Added InsertChar overload
- Fixed InsertChar tag offset calculations
- Added DeleteChar() method
- Added Combine() method for folding lines
- Fixed Delete() method, no longer allocates wasted Line object and now
  copies all properties when swapping nodes
- Delete() method now updates document line counter

svn path=/trunk/mcs/; revision=37824